US3778975A - Gas chromatography - Google Patents

Gas chromatography Download PDF

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Publication number
US3778975A
US3778975A US00193708A US3778975DA US3778975A US 3778975 A US3778975 A US 3778975A US 00193708 A US00193708 A US 00193708A US 3778975D A US3778975D A US 3778975DA US 3778975 A US3778975 A US 3778975A
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US
United States
Prior art keywords
sample
conduit
carrier gas
sample injector
gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00193708A
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English (en)
Inventor
D Deans
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Imperial Chemical Industries Ltd
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Imperial Chemical Industries Ltd
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Publication date
Application filed by Imperial Chemical Industries Ltd filed Critical Imperial Chemical Industries Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/04—Preparation or injection of sample to be analysed
    • G01N30/16—Injection
    • G01N30/18—Injection using a septum or microsyringe

Definitions

  • the peaks corresponding to components emerging from the column have tails", i.e., the peaks are not symmetrical, a small' quantity of the component emerging over a period after the passage of the main part of the peak. Such tailing complicates interpretation of the results, especially when a peak of the second component occurs during passage of a tail.
  • Tailing is in some cases due to the nature of the packing in the chromatographic column; in particular packings of which the partition co-efficient of the component between the packing and the vapour phase declines with increasing concentration of the component in the vapour phase (i.e., a smaller proportion of the component is sorbed as its concentration increases) show this effect.
  • packings of which the partition co-efficient of the component between the packing and the vapour phase declines with increasing concentration of the component in the vapour phase i.e., a smaller proportion of the component is sorbed as its concentration increases
  • tailing is often caused also by geometrical factors.
  • unswept volume a volume within a gas chromatographic apparatus communicating with the gas chromatographic stream but through which no major flows of the stream or of carrier gas occur during normal operation of the apparatus.
  • Such unswept volume includes not only recesses but also volume caused by angles especially acute or right angles in conduits along which the gas is passing.
  • This invention is based on providing small bleeds of gas through unswept volumes from or to the chromatographic gas stream, so that any sample or component entering the unswept volumes will bleed away, preferably to the atmosphere, rather than contributing to a tail, or so that flow of gas to the chromatographic gas stream will prevent sample entering the unswept volume or carry it quickly back to the said stream.
  • the invention enables relatively large unswept volumes to be tolerated and this may so reduce constraints on the design of chromatographic systems that several small unswept volumes may be rendered unnecessary.
  • the invention comprises a gas chromatographic system in which a restricted vent from the chromatographic gas stream is provided from an unswept volume.
  • the invention also comprises a union piece for connecting units of a gas chromatographic system through which union piece gas is to flow, which union piece encompasses an unswept volume, the union piece comprising a restricted vent from the chromatographic gas stream from the unswept volume.
  • the invention also comprises a sample injector for a gas chromatographic system which comprises a restricted vent from the chromatographic gas stream from an unswept volume.
  • the sample injector may comprise a carrier gas conduit, an injection conduit for leading from a septum holder to the carrier gas conduit in a substantially straight line to permit the passage down it of a hypoder' mic needle, and a restricted vent from the injection conduit to the atmosphere surrounding the sample injector.
  • the carrier gas conduit is provided on its output side with means to connect it to a chromatographic column which comprises a restricted vent from an unswept volume encompassed by the said means to the atmosphere surrounding the sample injector.
  • the restricted vents are supplied outside the apparatus with carrier gas at a higher pressure than that applying to them within the apparatus, (for example, if they communicate withthe atmosphere surrounding the apparatus, by providing the apparatus with a vessel surrounding the restricted vents, to which an elevated pressure is applied), a flow of gas to the chromatographic gas stream will prevent sample entering the unswept volume or carry it quickly back to the said stream.
  • the sample injector comprises means to heat the carrier gas conduit.
  • the carrier gas conduit and the injection conduit may be formed in a metal block, preferably of high thermal conductivity, for example a brass block, which is provided with means for heating it, for example an electrical heating coil.
  • the septum holder may be mounted on a sleeve for fitting in the injection conduit, the sleeve being formed, if it projects past a restricted vent in the injection conduit, with a hole in its wall corresponding to the inlet of the restricted vent.
  • the means to connect the sample injector to the chromatographic column may comprise an enlarged outlet portion of the carrier gas conduit with walls adapted to form the socket of a cone and socket joint with a tube leading to a chromatographic column, the inlet end of which is formed as a corresponding cone.
  • a restricted vent is preferably provided to lead from between the tube and the enlarged part of the carrier gas conduit on the output side of the cone and socket joint to the atmosphere.
  • sample injector according to the invention will now be described with reference to the drawing which shows a cross-section through the sample in- .duit, into'which is inserted a sleeve 6 on which is mounted a septum holder 7 containing a septum 8.
  • Restricted vents 11 and 12 lead respectively from sleeve 6 which has a port 13 passing through its wall in register with vent 1 1 and a gap between tube 9 and outlet 3. Both restricted vents are capillaries held in position by conventional compression couplings l9 and 14 which act on deformable metal olives 15 and 16.
  • a blind ended bore 17 is provided for accommodating an electrical cartridge heater (not shown)
  • the inlet to conduit 2 is united by soldering to the inserted end of an inlet tube 18 which is wound round the block 1 to form a helix.
  • the apparatus acts as follows:
  • the block 1 is heated by a heater in bore 17 and carrier gas passed through the helical tube 18, during which movement the carrier gas becomes warm, and through conduit 2.
  • the needle of a hypodermic syringe When it is desired to inject a sample, the needle of a hypodermic syringe is pushed through the septum 8 and down sleeve 6 until its tip enters conduit 2. Liquid sample is then injected from the needle into conduit 2 and the needle is withdrawn.
  • a re stricted vent from a gas stream may in general function as a vent to the gas stream if desired if an appropriate pressure drop across it is provided.
  • a sample injector for a gas chromatographic systern which comprises a block of high thermal conductivity comprising a carrier gas conduit and a sample injection conduit leading to the carrier gas conduit in a substantially straight line, means to heat the block, a restricted vent from the sample injection conduit to an atmosphere surrounding the sample injector, a sleeve fitting into the injection conduit and permitting free flow to the restricted vent in the injection conduit and a septum holder mounted on the sleeve and spaced away from the heat conducting block.
  • a sample injector as claimed in claim 1 in which the carrier gas conduit is provided on its output side with means to connect it to a chromatographic column which means comprises a restricted vent from an unswept volume encompassed by the said means to an atmosphere surrounding the sample injector.
  • a sample injector as claimed in claim 1 in which the restricted vent from the injection conduit has 1 the sample vaporises and expands thus forcing part of the sample back into sleeve 6 and also back up conduit 2 and between the tube 9 and outlet 3.
  • the sample in conduit 2 passes through in a block, but sample passing into sleeve 6 passes, because of the positive pressure in the apparatus, up the sleeve and means to supply it with carrier gas at a higher pressure than that applying to it on its chromatographic gas stream side.
  • a sample injector as claimed in claim 3 which comprises a vessel to which carrier gas at an elevated pressure may be applied and which surrounds the restricted vent.
  • a sample injector as claimed in claim 1 in which the block of comprises a metal of high thermal conductivity which is provided with an electrical heating coil.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Treatment Of Liquids With Adsorbents In General (AREA)
US00193708A 1970-11-09 1971-10-29 Gas chromatography Expired - Lifetime US3778975A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5311770A GB1372356A (en) 1970-11-09 1970-11-09 Gas chromatography

Publications (1)

Publication Number Publication Date
US3778975A true US3778975A (en) 1973-12-18

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00193708A Expired - Lifetime US3778975A (en) 1970-11-09 1971-10-29 Gas chromatography

Country Status (5)

Country Link
US (1) US3778975A (enExample)
DE (1) DE2155690A1 (enExample)
FR (1) FR2113664A5 (enExample)
GB (1) GB1372356A (enExample)
NL (1) NL7115124A (enExample)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4730480A (en) * 1986-06-24 1988-03-15 Microscale Organic Laboratory Corporation Gas chromatograph collection device and process
US5252109A (en) * 1991-04-24 1993-10-12 Carlo Erba Strumentazione S.P.A. Gas chromatographic injector
WO1996011397A1 (de) * 1994-10-05 1996-04-18 Ufz - Umweltforschungszentrum Leipzig-Halle Gmbh Reduktionsofen und verfahren zur quantitativen deuteriumbestimmung in wasserstoffhaltigen proben
US20030079523A1 (en) * 2001-10-29 2003-05-01 Teresa Lechner-Fish Carrier gas pre-heat system for gas chromatograph
US20170030626A1 (en) * 2015-07-27 2017-02-02 Mitegen, Llc Cryogenic cooling apparatus, methods, and applications
WO2021228362A1 (de) 2020-05-11 2021-11-18 Wacker Chemie Ag Verfahren zur quantifizierung eines spurenkomponenten-peaks in einem chromatogramm

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3132638A1 (de) * 1981-08-18 1983-03-10 Vsesojuznyj naučno-issledovatel'skij i konstruktorskij institut chromatografii, Moskva Verfahren zur einfuehrung von proben in einem gaschromatografen und vorrichtung zur durchfuehrung dieses verfahrens
FR2721838A1 (fr) * 1994-06-30 1996-01-05 Inst Francais Du Petrole Dispositif perfectionne de separation des phases d'un echantillon fluide
GB9904225D0 (en) * 1999-02-25 1999-04-21 Egmond W M A Injection liner with integral profiling such that it can be fitted with an injection septum and cap

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3498027A (en) * 1967-09-11 1970-03-03 Varian Associates Stream splitter for gas chromatography
US3656277A (en) * 1969-03-28 1972-04-18 Tno Method and device for gas chromatography

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3498027A (en) * 1967-09-11 1970-03-03 Varian Associates Stream splitter for gas chromatography
US3656277A (en) * 1969-03-28 1972-04-18 Tno Method and device for gas chromatography

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4730480A (en) * 1986-06-24 1988-03-15 Microscale Organic Laboratory Corporation Gas chromatograph collection device and process
US5252109A (en) * 1991-04-24 1993-10-12 Carlo Erba Strumentazione S.P.A. Gas chromatographic injector
WO1996011397A1 (de) * 1994-10-05 1996-04-18 Ufz - Umweltforschungszentrum Leipzig-Halle Gmbh Reduktionsofen und verfahren zur quantitativen deuteriumbestimmung in wasserstoffhaltigen proben
US20030079523A1 (en) * 2001-10-29 2003-05-01 Teresa Lechner-Fish Carrier gas pre-heat system for gas chromatograph
US6776025B2 (en) * 2001-10-29 2004-08-17 Daniel Industries, Inc. Carrier gas pre-heat system for gas chromatograph
US20170030626A1 (en) * 2015-07-27 2017-02-02 Mitegen, Llc Cryogenic cooling apparatus, methods, and applications
US11473826B2 (en) * 2015-07-27 2022-10-18 Mitegen, Llc Cryogenic cooling apparatus, methods, and applications
WO2021228362A1 (de) 2020-05-11 2021-11-18 Wacker Chemie Ag Verfahren zur quantifizierung eines spurenkomponenten-peaks in einem chromatogramm

Also Published As

Publication number Publication date
FR2113664A5 (enExample) 1972-06-23
GB1372356A (en) 1974-10-30
NL7115124A (enExample) 1972-05-12
DE2155690A1 (de) 1972-05-25

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